Deformation and Energy Absorption of Steel Square Tubes With Optimized Shape Design

Abstract Square crush tubes have been widely used as impact energy absorbers in automotive and railway vehicles. In this paper, a square tube with vertical plates and dents has been designed to increase the controllability and stability of crash performance. Vertical plates are welded perpendicularly to the side walls of the tube, which increase the transverse stiffness and ensure the tube crashes in longitudinal direction under impact not in ideal axial direction. Dents have been put on the side walls near the front end of the tube to ensure the collapse always start from the front and progress gradually to the end. To validate the design, finite element analysis (FEA) and various experiments has been conducted and evaluated. Firstly, the numerical simulations were carried out using the software LS-DYNA. Then, four specimens were manufactured and tested. The crash velocity, tube deformation and impact force showed great agreement between the simulations and test results. The number of tubes, tube wall thickness, cross-section, trigger plates and dents arrangement can be adjusted to meet the requirements of different applications. In one application, the energy absorbing device with four crush tubes provided progressive controlled collapse with energy absorbing capacity of 1.22MJ and impact force less than 4450kN. This robust crush tube design has been successfully applied in multiple railway vehicles and also has the potential to be applied in other industries such as automotive vehicles.